The first map is over, the favorite lost it, and the match-winner price on the desk has moved. What does that number mean now? It is the market pricing the series from 1-0, not from scratch: the leader needs one more map, and the trailing team needs two in a row. The price beside each name is the answer to that narrower question.
The question changed when the map ended
A prematch match price asks who wins the series. A live match price after map one asks who wins the series from here, and those are different numbers even for the same two teams. As the CS2 odds page frames it, a team can lose the opening map and still win the match, which is exactly what the live price is weighing: how likely that comeback is, given everything the market knows now.
The prematch favorite shortening after winning map one is not the market repeating itself. It is a new, easier question getting a shorter answer.
The path math underneath
In a best-of-three at 1-0, the leader takes the series by winning either remaining map, while the trailing team must take both. If the two teams were evenly matched on each map, that path difference alone would make the leader roughly a 3-to-1 favorite for the series: the trailer wins only the one case in four where they take map two and map three. In a best-of-five the same counting applies with more branches, and the market guide keeps the habit that matters here: always ask what the market needs to happen, not just who wins.
When a live price moves less than the path math suggests, the market is telling you the map that just ended changed its mind about the teams, not just about the score.
A moved price is not a suspended one
A price that moved is the market working; a price that vanished is the market paused. If the number is there, read it, but read it with the clocks: the coverage page explains why this desk withholds prices when freshness is unconfirmed, and why a fresh board can still hold an unchanged price. What you should not do is reverse-engineer the game state from the move itself: the site's Dota 2 page is explicit that game state needs its own sources and should not be inferred from an odds movement.
What to take from it
A live series price is a verdict with a score attached. Read it as the market's answer to who finishes the path, compare it against the prematch number to see what the map changed, and let the freshness label decide whether the number is current enough to trust.
From 1-0, the question is no longer who is better. It is who closes, and the price is priced exactly so.